Our overall goal is to improve utilization of hydroxyurea for adults with sickle cell disease. Hydroxyurea (HU) therapy is currently the only disease-modifying pharmaceutical agent available to treat adult patients with sickle cell anemia (SCA). A recent NIH consensus panel reviewed the available evidence regarding HU treatment for SCD and found it to be safe, efficacious, and effective (Brawley et al., 2008). This review also found HU to be highly underutilized. We have previously identified provider barriers to the use of HU which included many concerns about patient compliance and concerns over toxicity. As SCD is a rare disorder, a large multistate study will be needed to test interventions to improve utilization of HU in this patient population. The design of this large trial will entail having hem/onc providers participate in a web based intervention to improve knowledge and decrease barriers to prescribing HU and then randomize their patients to an intervention to improve adherence. The primary aim of this large multicenter trial will be to demonstrate that the intervention decreases hospital and emergency room visits for adults with SCD eligible for HU. The purpose of this R34 grant is to gather data needed in order to do the larger study. With this grant we well characterize the patients seen by community hematologist/oncologists (Aim1), refine and test (Aim 2) a behavioral intervention designed to reduce the informational and attitudinal factors which contribute to hematologists/oncologists reluctance to prescribe HU to SCD patients and finally assess the feasibility (Aim 3) of training clinic staff to provide problem solving to patients to improve adherence to HU. Based on data from our previous studies on provider identified barriers to HU our central hypothesis is that lack of knowledge by hematologists/oncologists regarding the management of HU, as well a lack of appropriate tools to overcome barriers to its use, significantly contribute to the underutilization of HU.